US3973920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1975-08-11
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Granted: 1976-08-10
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Expires: 1995-08-11
Abstract
Abstract This invention relates to a magnetic recording medium, which comprises a first protective plating layer consisting of at least one selected from the group consisting of rhenium, osmium, ruthenium, chromium, rhodium and mixtures thereof, provided on a ferromagnetic thin layer plated on a non-magnetic base material by a plating method, and a second protective plating layer consisting of at least one selected from the group consisting of silver, gold, copper, platinum, palladium, nickel-phosphorus alloys and mixtures thereof, further provided on the first protective plating layer.
Inventors
- 👤 Eiichi Tadokoro
- 👤 Tatsuji Kitamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:06
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/726; G11B5/7262; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12597; Y10T428/12611; Y10T428/12618; Y10T428/12729; Y10T428/12736; Y10T428/1275; Y10T428/12771; Y10T428/12778; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12854; Y10T428/12861; Y10T428/12868; Y10T428/19; Y10T428/192; Y10T428/197; Y10T428/198
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
81 words
A magnetic recording medium, which comprises a first protective plating layer consisting of at least one selected from the group consisting of rhenium, osmium, ruthenium, chromium, rhodium and mixtures thereof, provided on a ferromagnetic thin layer plated on a non-magnetic base material by a plating method, and a second protective plating layer consisting of at least one selected from the group consisting of silver, gold, copper, platinum, palladium, nickel-phosphorus alloys and mixtures thereof, further provided on the first protective plating layer.
Claim 2
Dependent Claim
81 words
A magnetic recording medium, which comprises a first protective plating layer consisting of at least one selected from the group consisting of rhenium, osmium, ruthenium, chromium, rhodium and mixtures thereof, provided on a ferromagnetic thin layer plated on a non-magnetic base material by a plating method, and a second protective plating layer consisting of at least one selected from the group consisting of silver, gold, copper, platinum, palladium, nickel-phosphorus alloys and mixtures thereof, further provided on the first protective plating layer.
Claim 3
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the first protective plating layer has a thickness of 0.01 to 2 microns.
Claim 4
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the second protective plating layer has a thickness of 0.01 to 2 microns.
Claim 5
Dependent Claim
22 words
The magnetic recording medium of claim 1, wherein the first and second protective plating layers are provided by electroplating or electroless plating.
Claim 6
Dependent Claim
22 words
The magnetic recording medium of claim 1, wherein the non-magnetic material is selected from aluminum alloys, magnesium alloys, glass, ceramics and plastics.
Claim 7
Dependent Claim
27 words
The magnetic recording medium of claim 1, wherein the ferromagnetic thin layer is at least one selected from the group consisting of Co alloys and Co-Ni alloys.
Claim 8
Dependent Claim
25 words
The magnetic recording medium of claim 6, wherein the Co alloys are selected from the group consisting of Co-P, Co-B, Co-Cu-P, Co-Cu-B, Co-Cr-P and Co-Cr-B.
Claim 9
Dependent Claim
26 words
The magnetic recording medium of claim 6, wherein the Co-Ni alloys are selected from the group consisting of Ci-Ni, Co-Ni-P, Co-Ni-B, Co-Ni-Cu-P, Co-Ni-Cu-B, Co-Ni-Cr-P and Co-Ni-Cr-B.
References Cited (Backward Citations)
US3460968A
Cited
US3607149A
Cited
US3471272A
Cited
US3466156A
Cited
US3682604A
Cited
US3717504A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |